Can you explain GABAs role in alcohol withdrawal?

[ashleigh_0804]

I have been an RN for about a year and a half. Recently transferred to an ICU and have been researching after work everyday to learn more about the cases I saw that day and gain better idea of patho and improve critical thinking skills. Recently had a patient going through DTs. While I know the usual treatment and things to look for...still trying get a grasp on the cause. Can you explain the effect of GABA and what it does during alcohol withdrawal? Also, I know we bolus these people to keep them hydrated. My patient was getting maintenance fluids and they kept giving him boluses...but his BUN was 3. If you are high, you are dry, right? So what's the logic behind adding boluses of LR, even if their BUN is so low it would indicate they weren't dry? Creat and GFR normal, urine output excellent. BP elevated (180's/90's). Was worried about fluid overload, but preceptor said not to. Not to mention all the fluids from electrolyte replacement and banana bags.

[ashleigh_0804]

Oops -- BP would be 220s/115 at times, all over the place but also with a very high map.

[Corey Narry, MSN, RN, NP]

You have to think about neurotransmitters to understand the pathophysiology of alcohol withdrawal. The brain has receptors for two types of neurotransmitters, one causing excitation and the other causing inhibition of brain impulses. GABA is basically neuro-inhibitory or decreased brain excitability, NMDA is the opposite and causes neuro-excitation or increased brain excitability.

Alcohol affects GABA and NMDA in the following ways:

• enhances GABA effects on the neuroreceptors
  
• in chronic alcohol exposure over time, GABA neuroreceptor effects decrease, thus resulting in tolerance to alcohol consumption
  
• inhibits NMDA neuroreceptors
  
• in chronic alcohol exposure over time, NMDA upregulates to compensate
  
• abrupt cessation of alcohol causes the upregulated NMDA to accumulate and become transmitted thus resulting in excitability, anxiety, tremors, and in severe cases seizures.
  

The standard management of alcohol withdrawal is to monitor CIWA Scores. High CIWA scores are treated with benzodiazepines which has a GABA effect.

I am not sure why this patient was getting boluses on top of the maintenance fluids he was getting based on the information you provided. I am not saying it's wrong but that is something you should ask the provider who was ordering it so you would know the rationale.

Further reading: http://www.aafp.org/afp/2004/0315/p1443.html